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United States Patent Ofice Re. 26,951 Reissued 'Oct. 6, 1970 26,961HERBICIDES Philip C. Hamm, Glendale, and Angelo .l. Speziale, Kirkwood,Mo., assignors to Monsanto Company, St. Louis, Mo., a corporation ofDelaware No Drawing. Original No. 2,863,752, dated Dec. 9, 1958, Ser.No. 455,740, Sept. 13, 1954. Application for reissue May 27, 1968, Ser.No. 741,828

Int. Cl. A01n 9/20 US. Cl. 71-118 19 Claims Matter enclosed in heavybrackets appears in the original patent but forms no part of thisreissue specification; matter printed in italics indicates the additionsmade by reissue.

ABSTRACT OF THE DISCLOSURE Herbicidal use and compositions having theformula X R O wherein Y is a halogen atom; R is selected from the groupconsisting of alkyl, alkenyl, alkynyl, lzaloalkyl, haloa'lkenyl andlzuloulkynyl each having a maximum of six carbon atoms; and X isselected from the group consisting of hydrogen, halogen, nitro and alkylhaving a maximum of four carbon atoms.

This invention relates to herbicidal compounds and methods for theiruse. More particularly, this invention relates to methods of inhibitingthe growth of grasses in the presence of other vegetation.

Many chemical compounds are known to be deleterious to the growth ofvegetation and to have herbicidal eliects under specific conditions,some of which are known to be quite efiective at low levels ofapplication. It is, however, a more difiicult problem to provide usefulherbicides for selective activity on undersirable plants, but which areotherwise harmless to other vegetation. Compounds of this type areknown, being primarily useful in eliminating broad leaf plants fromgrasses or grass-like cereal crops. This herbicidal activity isfrequently related to the leaf area exposed to the herbicide, the plantswith larger leaf areas being more susceptible to the contact herbicides.

It is the primary purpose of this invention to provide a new and usefulclass of general herbicides and methods for their use. A further purposeof the invention is to provide methods of destroying grasses in thepresence of broad leaf plants. Still further purposes of the inventionwill be apparent from the following disclosure.

In accordance with this invention, it has been discovered that compoundsof the following chemical structure have unusual and valuable herbicidalactivities wherein Y is a halogen atom including chlorine, bromine,iodine and fluorine, wherein R is a radical selected from the group ofalkyl radicals having up to six carbon atoms, the alkenyl radicalshaving up to six carbon atoms, the alkynyl radicals having up to sixcarbon atoms, the haloalkyl radicals having up to six carbon atoms, thehaloalkenyl radicals having up to six carbon atoms, the haloalkynylradicals having up to six carbon atoms, the oxaalkyl radicals having upto six carbon atoms, and wherein x is selected from the group consistingof a hydrogen atom, the halogen atoms, a nitro radical, and the alkylradicals having up to four carbon atoms.

Suitable compounds for use in the practice of this invention are thosewhere in the R group is selected from the group of radicals consistingof methyl, ethyl, propyl, isopropyl, n-butyl, primary isobutyl,secondary isobutyl, tertiarybutyl, n-amyl, the branch chain amyls, thehexyl radicals, vinyl, ally], crotyl, methallyl, methylvinyl radicals,propargyl, 2'chloroethyl, Z-chloropropyl, 3-chloropropy], chloromethyl,the Z-bromopropyl radicals, 2- chloroallyl, 3-chloroallyl,2,3-dichloropropyl, 3-chloro-2- butenyl, chloropropargyl,Z-methoxyethyl, 2-ethoxyethyl, 2-ethoxyethoxyethyl, the methoxybutylradicals, 3- methoxy propyl, 3-ethoxy propyl, 3-isobutoxy propyl, 4-n-propyl and n-propoxy propyl.

The above defined a-haloacetamides having both aliphatic and aromaticnitrogen substituents may in general be prepared by reacting the acidchloride of lit-haloacetic acid with an excess of a nitrogen-substituedaniline, the ring of said aniline may, if desired, contain halogen,alkyl (having up to 4 carbon atoms) and nitro radicals. The herbicidalcompounds are made from the secondary amines by selecting amines withthe desired configuration. If the reagents are liquids, the preparationwill merely involve mixing the said reagents under refrigeratedconditions so as to prevent an excessive rate of reaction. lt isfrequently advantageous to conduct the reaction in the presence of astoichiometric amount of caustic soda, and it is often desirable toconduct the reaction in the presence of a suitable solvent, for exampleethylene dichloride. The N-substitued a-haloacetamides, otherwise knownas the N-substituted acetanilides, may be separated from the reactionmixture and from the incident impurities by distillation, or byfractional crystallization from the solvent medium or from othersuitable solvents in the case that the desired product is a solidsubstance. Further details in the preparation of these compounds are setforth in the following examples.

EXAMPLE I A 500 ml. reaction flask was charged with 16.7 g. N-2-chloroallyl aniline, 24 g. of 20% sodium hydroxide solution and ml. ofethylene dichloride. The mixture was cooled to 10 C. and whilemaintaining this temperature, 13.6 g. of chloroacetyl chloride wasgradually added over a ten minute period. When the combination ofreagents was complete, the mixture was allowed to warm gradually to 10C. The organic layer which separated from the aqueous phase was washedsuccessive ly with dilute hydrochloric acid, dilute sodium bicarbonateand finally with water. After drying with magnesium sulfate, theethylene dichloride was evaporated at reduced pressure. The resultingliquid product which was fractionally distilled and the substituentboiled at 138 C. at 0.7m m. total pressure, was identified as N-Z-chloroalyl-a-chloroacetanilide.

EXAMPLE II A reaction flask was charged with 21.4 g. of N-methylaniline,48 g. of 20% sodium hydroxide solution and 100 ml. of ethylenedichloride. The flask and its contents was cooled to -l0 C. and 27 g. ofchloroacetyl chloride gradually added over a period of 15 minutes. Afterstirring until the mixture was warmed to 5 C., the resulting organicphase was separated and washed with dilute hydrochloric acid and water.Upon the evaporation of the ethylene dichloride a solid product wasobtained) 7 which was recrystallized from aqueous ethanol. The

white crystalline product having a melting point of 67 68.5 C. wasidentified as N-methyl-a-chloroacetanilide.

EXAMPLE III Using the procedure of Example II except that the N- methylaniline was replaced by N-butyl aniline, a product resulted which wasidentified as N-butyl-a-chloroacetanilide.

EXAMPLE IV A Wild oat B Cheat grass C Rye D Buckwheat E Mustard 20 FBeet G Cotton H Cucumber The relative value of each compound withrespect to its herbicidal effect on the various plants is indicated by anumber as follows:

No pyhtotoxicity. l Slight phytotoxicity. 2 Moderate phytotoxicity. 3Severe phytotoxicity.

'1 ABLE A t l) J L it It wt-hloroacetanilide (control) n 2 ti 0 ti 2 ItIt Netliyl-a-ehloroaeetanilide .t l u tt .3 ll 2N'.2'chloroallyl-a-elilorouectanilltle. d 1 l t) 1 t) l p, a-dlClllOlOacetanilidc (control) it it (I tt tl 0 t) Nethylp, u-dichioroaeetanilide .5 3 U it 1 U U When the N-aliphatic substitutedacetanilides are used in heavier rates of application, they are quiteeffective over a broader range of botanical groups and at such levelsthe specificity with respect to grasses is less evident. The followingdata demonstrates this general herbicidal utility at a lb. per acrelevel of application.

A B C l) E l (1 ll N-ethyla-ehloroacetanilide .Z 3 3 U 1 3 U 1N-urethyl-a-chloroacotunilide. 3 3 3 3 3 3 U 5N-hutyl-mchloroacetanilidm 3 3 3 1 3 3 It i N-ethyl-p,n-(lichloroaeetanilide 3 3 3 l 2 3 I)N-LZ-ehtoroallyl-a-chloroaeetanilido 3 3 3 l 1 3 (l 1 To demonstrate thelack of herbicidal effect of homologous compounds which do not have thestructure, p-adichloroacetanilide was studied at lbs. per acre. Thefollowing herbicidal effects were observed.

A B U l) E F H ll p-a-dichloroacetanllide U t) O In addition to theabove data demonstrating critical characteristics of effectivea-haloacetanilides, over 200 different whaloamides have been studied todetermine the effects of substituents on the alpha carbon atom and othersubstituents on the amide nitrogen atom. Since analogous propionamidesand butyramides are not effective, it is apparent that the lack of acarbon substituent (as in the acetarnide) is critical. Since compoundswith two and three halogen atoms on the a-carbon atom are notherbicidal, it appears that a single or halogen atom is necessary. Atthe same time it was established that bromine and iodine analogues hadsubstantially equivalent pre-emergence value and even higher contactherbicidal activity. These screening procedures indicated that thesecond substituent must be a relatively short chain aliphatic radical.

Valuable herbicidal effects will be observed by application of smallamounts, for example as low as 1 lb. of active component per acre aswell as high concentrations, for example lbs. per acre. The selectiveactivity on grasses is exhibited at lower rates of applica tion, forexample from 2 to 15 lbs. per acre. For general application andherbicidal effect on both the grasses and the dicotyledonous plants, itwill be found necessary to use from 10 to 50 lbs. per acre.

Selective herbicidal activity with respect to several genera of grassesis illustrated by the data in the above tables. Other experiments runwith respect to plants of different genera, which have differentmetabolisms and physical characteristics indicate little or noinhibition of growth. The three botanical types, or genera, of grasseswhich are effectively controlled by means of the m-haloacetamide of thisinvention, embrace a large number of undesirable plants, or weeds,frequently found in vegetable crops. This invention is not limited toremoving grasses from broad leaf plants, since the selective activitywill be useful in removing weeds from corn, which belongs to a differentgenus of grass. Many other crops and particularly the broad leavedplants are inhibited by weeds of the wild oat, cheat and rye genera,which can be effectively controlled by the practice of this invention.In some instances there are minor herbicidal effects on dicotyledonousplants, and therefore optimum results may depend to some extent onexperience with respect to the activity of the particular N-substituteda-haloacetamide on the vegetable crop to be treated.

As demonstrated above, unusual grass specificity can be achieved atlower levels of application, whereas at higher levels of application theN-substituted u-haloacetamides exhibit a more general herbicidal effect.This provides another and quite different utility in the removal ofplants of a large number or all botanical genera. It will be apparentthat quite different effects can be obtained by modifying the method ofuse. For this reason an essential part of this invention is theformulation so as to permit a uniform predetermined application ofherbicide to the plant environment, for example the leaves or soilsurfaces, so as to produce the desired effect. By the proper selectionand proportioning of the various conditioning agents either liquid orsolid formulations can be prepared, and so as to adapt the herbicide forachieving the desired result with any conventional device for treatingplant or soil surfaces.

The solid formulations, frequently referred to as dusts may contain inaddition to the active ingredient, diluents or extenders, dispersingagent to prevent local high concentrations, and agents to facilitatedistribution in soil or soil waters. Suitable solid diluents are thosewhich render the compositions permanently dry and free flowing. Thushygroscopic materials are to be avoided unless the compositions alsocontain a separate substance to serve as an aid to the flowability.Effective solid diluents, preferably pulverulent or granular in form soas to be effective carriers for the active ingredient, are the naturalclays, such as china clays, the bentonites and the attapulgites; otherminerals in natural state, such as talc, pyrophyllite, quartz,diatomaceous earth, fullers earth, chalk, rock phosphate and sulfur; andthe chemically modified minerals, such as the acid washed bentonite,precipitated calcium phosphate, precipitated calcium carbonate andcolloidal silica. These diluents may represent a substantial portion,for example 50 to 98 percent by weight, of the entire formulation asapplied to plant or soil. More concentrated herbicides will requiredilution by the user in order to properly condition the soil for themost effective usage. The concentrated solid herbicidal formulations canbe used with less danger if it is mixed with the surface soil by meansof a disk-plow or harrow at the time of application.

The liquid compositions for herbicidal use may be solutions, or otherliquid dispersions. The choice of a liquid medium will depend to someextent upon the physical properties of the active ingredient. The N-substituted u-haloacetamides may be water-soluble and mere dissolutionwill then provide a usable formulation. Often the N-substitutedot-haloacetarnides are only limitedly soluble in Water and thereforeaqueous formulations will necessarily be dispersions of minute drops ofthe water-insoluble substances in suspension in an aqueous medium. Theknown water-insoluble substituted a-haloacetamides of this invention mayfirst be dissolved in a suitable organic solvent and the organicsolution of the active ingredient then incorporated in water or in anyaqueous medium to produce a heterogenous dispersion of the activeingredient in water.

One composition which aids in the effectivity of the herbicidalcomponent is a surface active agent which serves in providing uniformdispersions of all formulation components of both solid and liquidtypes, and may be anionic, cationic or non-ionic types and includesconventional soaps, such as the water-soluble salts of long chaincarboxylic acids, the amino soaps such as the amine salts of long chaincarboxylic acids, the sulfonated animal, vegetable and mineral oils,quaternary salts of high molecular weight acids, rosin soaps such assalts of abietic acid, sulfuric acid salts of high molecular weightorganic compounds, algin soaps, ethylene oxide condensated with fattyacids, alkyl phenols and mercaptans, and other simple and polymericcompositions having both hydrophilic and hydrophobic functions so as toenable the mixing of otherwise immiscible ingredients. Generally, thesurface active agents will be only a minor portion of the formulation asused, for example less than percent and frequently as low as 0.05percent. In general, concentrations of from 0.5 to 5 percent are foundto be optimum.

Many of the formulations are benefited by the incorporation of organicsolvents for the active components, such as the water-immiscible organicalcohols, ketones and hydrocarbons, for example isopropanol, benzene,acetone, methylethyl ketone, kerosene, and chlorinated hydrocarbons. Theproportions of such organic liquid additives will depend upon thesolubility properties of the active ingredient and may require as littleas l percent or as much as percent in order to provide a uniformlydistributed formulation which is capable of maintaining its distributedstate during storage, use and after application to the soil or plantsurfaces.

A useful formulation of the herbicidal compositions may involve thesolid or liquid concentrate of the active ingredient to which has beenadded formulation aids or conditioning agents so that the concentratesmay be mixed with a suitable extender or diluent in the field at thetime of use. Obviously, for this purpose the dispersing agents will bepresent in larger concentrations so that upon dilution with water or asolid extender, compositions containing optimum proportions ofdispersing agents and active component will be prepared. The solid orliquid formulations are preferably applied by mechanical equipmentinvolving spraying or spreading the formulation on soil or plantsurfaces being treated. For this purpose readily flowable compositionsare required, either liquid or solid in physical state. Thus a criticalaspect of the invention is the fluent carried without which the optimumherbicidal effects cannot be achieved.

Both the solid and the liquid formulations above described are useful inthe application of herbicides because they facilitate the uniformdistribution and aid in the destruction of undesirable plants bymaintaining the active ingredient in a form which enables the promptassimilation by the plant and the efficient utilization of its weeddestroying properties. The described conditioning agents enable theproper use to achieve the desired herbicidal effects by an unskilledoperator without elaborate equipment.

What is claimed is:

1. A method of inhibiting the germination of seeds and the growth ofplants which comprises treating the plant environment with a compoundhaving the structural formula wherein Y is a halogen atom, wherein R isa radical selected from the group of alkyl radicals having up to sixcarbon atoms, the alkenyl radicals having up to six carbon atoms, thealkynyl radicals having up to six carbon atoms, the halo-alkyl radicalshaving up to six carbon atoms, the halo-alkenyl radicals having up tosix carbon atoms, and the halo-alkynyl radicals having up to six carbonatoms; and wherein x is selected from the group consisting of a hydrogenatom, the halogen atoms, a nitro radical, and the alkyl radicals havingup to four carbon atoms, said compound being added in an amount andconcentration sufficient to inhibit the seed germination and growth.

2. A method of inhibiting the germination of seeds and the growth ofplants which comprises treating the plant environment with N-methyliz-chloroacetanilide, in an amount and concentration sufficient toinhibit the seed germination and growth.

3. A method of inhibiting the germination of seeds and the growth ofplants which comprises treating the plant environment with N-ethyla-chloroacetanilide, in an amount of concentration suflicient to inhibitthe seed germination and growth.

4. A method of inhibiting the germination of seeds and the growth ofplants which comprises treating the plant environment with N-butyla-chloroacetanilide, in an amount and concentration sufiicient toinhibit the seed germination and growth.

5. A method of inhibiting the germination of seeds and the growth ofplants which comprises treating the plant environment withN-2-chloroallyl a-chloroacetanilide, in an amount and concentrationsufficient to inhibit the seed germination and growth.

6. A method of inhibiting the germination of seeds and the growth ofplants which comprises treating the plant environment withN-ethyl-p-a-dichloroacetanilide, in an amount and concentrationsuflicient to inhibit the seed germination and growth.

7. A composition for inhibiting the germination of seeds and the growthof plants which comprises a herbicide conditioning agent and in anamount sufficient to exert a herbicidal action a compound of thestructure wherein Y is a halogen atom, wherein R is a radical selectedfrom the group of alkyl radicals having [up] from two to six carbonatoms, the alkenyl radicals having up to six carbon atoms, the alkynylradicals having up to six carbon atoms, the haloalkyl radicals having upto six carbon atoms, the halo-alkenyl radicals having up to six carbonatoms, and the halo-alkynyl radicals having up to six carbon atoms; andwherein x is selected from the group consisting of a hydrogen atom, thehalogen atoms, a nitro radical, and the alkyl radicals having up to fouratoms.

[8. The composition defined by claim 7 wherein the compound is N-methyla-chloroacetanilideJ 9. The composition defined by claim 7 wherein thecompound is N-ethyl a-chloroacetanilide.

10. The composition defined by claim 7 wherein the compound is N-butyla-chloroacetanilide.

11. The composition defined by claim 7 wherein the compound isN-2-chloroallyl a-chloroacetanilide.

12. The composition defined by claim 7 wherein the compound isn-ethyl-p-a-dichloroacetanilide.

13. A composition for inhibiting the growth of grass in the presence ofcrop plants, which comprises a surface active agent and in an amountsufficient to exert herbicidal action a compound of the structurewherein Y is a halogen atom, wherein R is a radical selected from thegroup of alkyl radicals having [up] from two to six carbon atoms, thealkenyl radicals having up to six carbon atoms, the alkynyl radicalshaving up to six carbon atoms, the halo-alkyl radicals having up to sixatoms, the halo-alkenyl radicals having up to six carbon atoms, and thehalo-alkynyl radicals having up to six carbon atoms; and wherein x isselected from the group consisting of a hydrogen atom, the halogenatoms, a nitro radical, and the alkyl-radical having up to four carbonatoms.

[14. The composition defined by claim 13 wherein the compound isN-methyl a-chloroacetanilideJ 15. The composition defined by claim 13wherein the compound is N-ethyl a-chloroacetanilide.

16. The composition defined by claim 13 wherein the compound is N-butyla-chloroacetanilide.

17. The composition defined by claim 13 wherein the compound isN-Z-chloroallyl a-chloroacetanilide.

18. The composition defined by claim 13 wherein the compound isN-ethyl-p-ot-dichloroacetanilide.

19. The composition defined by claim 7 wherein Y is a chlorine atom, Ris an alkyl radical containing from two to six carbon atoms, and x is ahydrogen atom.

20. The composition of claim 13 wherein Y is a chlorine atom, R is analkyl radical containing from two to six carbon atoms and x is hydrogen.

2]. The composition defined by claim 7 wherein said herbicideconditioning agent is in granular form.

References Cited The following references, cited by the Examiner, are ofrecord in the patented file of this patent or the original patent.

UNITED STATES PATENTS 2,622,976 12/1952 Hitchcock et al, 2,636,8164/1953 Stewart. 2,649,363 8/ 1953 Swezey.

JAMES 0. THOMAS, 1a., Primary Examiner

